1. Technical Field
The present invention relates to an image display apparatus, an image display system, and an image display method.
2. Related Art
With recent development of various types of display technology, a display apparatus (image display apparatus) having a large-sized screen and high resolution has been widely used as a “dynamic poster” or a “bright and attention-attracting advertisement medium” for the purpose of so-called signage use. For example, a large-sized display apparatus containing LED (light emitting diode) as pixels for outdoor use, and a display apparatus including direct-view-type large screen liquid crystal display apparatus, plasma display apparatus, and projector for indoor use have been developed.
For signage application by using the respective display apparatus discussed above, there are advantages and disadvantages for each structure type. For example, the display apparatus containing the LED has high brightness and luminance, easy increase in screen size, and preferable weatherability. However, further increase in pixel density and improvement over color reproducibility and image quality are difficult. On the other hand, the direct-view-type display apparatus such as liquid crystal display device and plasma display apparatus has high degree of installation freedom such as easy establishment and reduced occupation area. As a result, cost reduction can be achieved. However, the freedom of display shape is low and power consumption is high, and thus this type of display apparatus is not appropriate for a display system which utilizes a floor as display unit, for example.
On the other hand, the display apparatus including the projector has advantages such as “high degree of freedom of display shape” and “separability from screen”. Thus, this display apparatus is expected to function as display system capable of using the floor as display unit or display system for other signage use which have not been realized by display apparatus in related art.
JP-A-2004-117579 discloses one of the technologies appropriately used for the display apparatus having the “high degree of freedom of display shape”, for example. JP-A-2004-117579 shows the technique which displays an image on a plurality of display screens when display surfaces are plural inner surfaces of polyhedron.
JP-A-2003-213868 discloses a display apparatus which has the advantages of “high degree of freedom of display shape” and “separability from screen”. According to a step type lighting device shown in JP-A-2003-213868, a light source for emitting illumination light is disposed behind a cross-board (board crossing tread-board) of a step equipped on a building, and a transmission type screen on which illumination light emitted from the light source is projected is installed on the cross-board of the step. In this step type lighting device, a converging lens is provided between the light source and the transmission type screen so as to converge illumination light from the light source on the transmission type screen. Furthermore, JP-A-2003-213868 discloses a step type display unit which controls illumination light such that one image can be produced by combining images formed on the respective cross-boards.
However, the technology disclosed in JP-A-2004-117579 only projects a continuous image on different surfaces by using one or plural projectors. Thus, when this method is applied to the step on the building, it is difficult to project a continuous image on each of the “tread-board” and “cross-board” of the step. Accordingly, this method is difficult to be applied to the display apparatus having the advantages of “high degree of freedom of display shape” and “separability from screen”.
According to the technology disclosed in JP-A-2003-213868, one light source is required for one “cross-board” of the step. Thus, the cost and labor for installation increase.